06 — 3D Printing

0. FDM / FFF 3D Printing

So first, I thought of something small and useful that I could print in under half an hour, and I decided to go with a safe guard for the USB-C cables as one of my instruments cable has been getting damaged at the bending point near the connector. Then I went into Printables to find a model that I could slice and print in the Prusa machine, and I found this one: USB-C Cable Protector. I downloaded the STL file and imported it into PrusaSlicer to prepare it for printing.

PrusaSlicer screenshot showing the USB-C cable protector model sliced for the Prusa CORE ONE, displaying print settings, estimated time, and filament usage
PrusaSlicer — sliced USB-C cable protector, showing print settings, estimated print time, and filament usage for the Prusa CORE ONE.

It worked perfectly!

1. Parametric Model

Well, I somehow have gotten slightly more familiar with FreeCAD, so I decided to overcome my fears and actually do this task. I happen to own a film camera that finding a cap for is either quite impossible, so I came up with the idea of doing a parametric model from the measurements of the lens I did using a caliper.

Photo of a film camera with a caliper measuring the outer diameter of the lens barrel to feed into the FreeCAD spreadsheet
Measuring the lens diameter with a caliper to feed into the FreeCAD spreadsheet.

Then I introduced the measurements into a FreeCAD spreadsheet and created a 3D model of the lens cap, using a combination of sketches, extrude, pocket and bevel features. I made sure to keep the design parametric by linking the dimensions in the sketches to the values in the spreadsheet, so I can easily adjust the size if needed.

Parametric 3D model of the custom lens cap in FreeCAD, shown alongside the spreadsheet with linked dimension values
FreeCAD — parametric lens cap model with spreadsheet-driven dimensions.

2. Slicing with PrusaSlicer

After designing the model, I exported it as a STEP file and imported it into PrusaSlicer to prepare it for printing. I chose a layer height of 0.2 mm for a good balance between print quality and speed, and I set the infill to 20% with a grid pattern for sufficient strength while keeping print time reasonable.

PrusaSlicer showing the sliced lens cap model with 0.2 mm layer height and 20% grid infill, layer preview visible
PrusaSlicer — sliced lens cap model with 0.2 mm layer height and 20% grid infill.

3. Printing

I 3D printed the model using the Prusa CORE ONE printer at the Aalto Fablab, and it came out great! The dimensions were slightly off on the first try and it couldn't fit the lens, so I went back to FreeCAD and adjusted the dimensions in the spreadsheet, which automatically updated the model, and then I re-exported it and printed it again, and this time it fit perfectly!

Photo of the finished 3D-printed lens cap sitting flush on the film camera lens, demonstrating a perfect fit
The finished lens cap fitting perfectly on the film camera lens.

4. Project Files

Download the files: 06_3dprint-project.zip